#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int bin_search(int* arr, int left, int right, int key)
{
	int mid;
	while (left <= right) {
		mid = (left + right) / 2;
		if (arr[mid] > key)right = mid - 1;
		else if (arr[mid] < key)left = mid + 1;
		else if (arr[mid] == key)return mid;
	}
	return -1;
}
int main()
{
	int found;
	int arr[11] = { 1,2,3,4,5,6,7,8,9,10 };
	int left = 0;
	int right = sizeof(arr) / sizeof(arr[0]) - 1;
	found = bin_search(arr, left, right, 7);
	printf("%d\n", found);
	return 0;
}